A large cannabis factory was literally sniffed out by an alert police officer with a keen sense of smell, a court heard.

Police at the scene of a large cannabis farm in Tharston. Picture Pete Walsh.

Sgt Neil Williams followed his nose when he smelled the drug in the air at Tharston Industrial Estate - and found hundreds of the illegal plants being grown.

At Norwich Crown Court yesterday, Judge Anthony Bate jailed Sang Dinh Nguyen, 51, and Thanh Pham, 30, for eight months after they both admitted being concerned in the production of cannabis at the Santareen Road unit.

Judge Bate accepted both men had acted as gardeners living in squalid conditions and said they were both “at the bottom of the chain”.

“There are others not before the court who were reaping the rewards of your horticultural endeavours.”

Peter Gair, prosecuting, said the men were found in the disused unit which was split into sections with 80 plants in each section at various stages of growth.

He said electricity had been bypassed to heat and light and plants and said: “It was a sophisticated cannabis factory.”

He said it was capable of producing a “significant quantity” of cannabis on a commercial scale.

Andrew Oliver, for both men, who had the help of a Vietnamese interpreter, said they both wanted to return home as soon as possible to be with their families.

He said Nguyen had a wife and five children back home and said that since being in custody he had had no contact with his family.

“He is anxious to get back home,” he said.

He said that Pham also wanted to return home to his family.

The factory was described as one of the biggest discovered in the area and at the time prompted a lot of attention.

At the end of the hearing, Judge Bate praised Sgt Williams for discovering the factory. He said it was a “good example of police work” and said he would be passing on his comments to Norfolk’s Chief Constable.